By Pat Hitchcock, U. C. Master Gardener

Four Tested Beans

Every region, including the Napa Valley, has a multitude of microclimates. This past summer, Napa County Master Gardeners decided to test pole bean varieties to see if we could ascertain which were best for our area. We chose four promising varieties: 'Violet Podded Stringless' (purple pods); 'French Duet' filet (green and yellow haricots verts); 'Black Seeded Blue Lake' (green); and 'Cascade Giant Stringless Snap' (green speckled with purple).

University trials of vegetables compare vigor, yield and quality. To do so, researchers grow the test varieties in large plots with multiple replications of each variety randomly arranged within the plots, and they repeat the tests over several years.

With the help of Dr. Marian Baldy, professor emerita of California State University at Chico, we Master Gardeners set up a more modest test. Every gardener who signed up for the trials would allocate enough garden space to plant five replications of each variety.

Each replication consisted of approximately three square feet for four plants of the same variety. We each had to grow 20 randomly arranged small blocks, five of each variety.

Our first challenge was to get the right number of plants up and growing. Spring was wet and cool, and we had to wait until May for the soil to warm up enough to plant.

For our data to be meaningful, each replication needed to have the same number of plants. This meant planting more seeds than we needed and thinning out extra plants later, or replanting if enough seeds didn't sprout.

The seedling stage is also when birds are interested in bean plants, so we protected the plants in various ways. Some participants used netting or strawberry baskets as barriers.

A second major challenge was creating support for the bean vines. Each

A Creative Trellis for Beans

By July some gardeners had to withdraw from the trials. Gophers and deer had found their plantings, and although the varmints rarely demolished all the beans, they rendered the data from those gardens useless.

At harvest time, a new challenge became apparent. Although we had carefully segregated beans by variety, the plants refused to grow only in their own section but wandered through neighboring trellis space, too. It's a good thing we planted varieties of different colors, although the green 'Duet' beans looked an awful lot like the 'Blue Lakes.' We became adept at figuring our which green bean was which, and we made educated guesses as to which replication our harvest came from.

We had no idea how many beans our plants might produce. At harvest time, we would pick all the beans from a single replication, record the weight, and then pick the next replication. The first picking from the first garden yielded more than 10 pounds of beans and took the gardener three hours to pick and record.

We picked through the July heat wave. We picked in August. We picked in September. I must confess: we tired of picking beans. However, friends, co-workers and the food bank appreciated our efforts. When we agreed that the test period was over, more than 590 pounds of beans had been harvested from the eight surviving trial plots. For most home gardeners, this would be too much of a good thing. As we learned, six feet of pole beans is probably enough for the average household.

We used a computer program supplied by our consulting scientist to analyze the data. We were hoping we could report that one variety out-performed all the others, but statistically, all the beans performed about the same. This result is probably due to the small size of our trial.

We can confirm that pole beans succeed in a lot of different Napa Valley microclimates. They need plenty of space, sturdy support, full sun, water and frequent picking. Protect from birds in the beginning; be prepared to deal with gophers and deer.

Unlike the university scientists, the Napa County Master Gardeners will not be repeating the bean trials next summer. One season of beans was enough for us. Next year we will put some other vegetable on trial. Lettuce, anyone?